// patterns/ShapeFactory2.java
// (c)2017 MindView LLC: see Copyright.txt
// We make no guarantees that this code is fit for any purpose.
// Visit http://OnJava8.com for more book information.

import patterns.shapes.*;

import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.util.HashMap;
import java.util.Map;

public class ShapeFactory2 implements FactoryMethod {
    Map<String, Constructor> factories =
            new HashMap<>();

    static Constructor load(String id) {
        System.out.println("loading " + id);
        try {
            return Class.forName("patterns.shapes." + id)
                    .getConstructor();
        } catch (ClassNotFoundException |
                NoSuchMethodException e) {
            throw new BadShapeCreation(id);
        }
    }

    public Shape create(String id) {
        try {
            return (Shape) factories
                    .computeIfAbsent(id, ShapeFactory2::load)
                    .newInstance();
        } catch (InstantiationException |
                IllegalAccessException |
                InvocationTargetException e) {
            throw new BadShapeCreation(id);
        }
    }

    public static void main(String[] args) {
        FactoryTest.test(new ShapeFactory2());
    }
}
/* Output:
loading Circle
Circle[0] draw
Circle[0] erase
loading Square
Square[1] draw
Square[1] erase
loading Triangle
Triangle[2] draw
Triangle[2] erase
Square[3] draw
Square[3] erase
Circle[4] draw
Circle[4] erase
Circle[5] draw
Circle[5] erase
Triangle[6] draw
Triangle[6] erase
*/
